Many people who have balance problems or weak muscles use some type of mobility device, such as an electric scooter or walker frame. These mobility devices typically require the user to use both hands to operate the device. The user steers the mobility device and either pushes the device with both hands or uses the hands to operate mechanical throttle and brake controls.
Because the user does not have a hand free for carrying any objects, such mobility aids frequently have some article carrier attached to it. Scooters often have a bicycle type basket mounted between the handlebars. Walker frames may have a tray, basket, or pouch attached to the frame. Users of walker frames with seats often place articles on the seat for transport.
Such article carrying containers are limited in size and lend themselves to transport of articles of only certain shapes and sizes. The carrying containers are typically attached to the upper part of the mobility device such that carrying heavy items can make the mobility device easier to overturn and harder to steer. Articles placed on a seat often fall off.
Thus, there is a need for a cart that users of mobility devices can use to safely carry larger and more awkwardly shaped articles than can be carried in conventional baskets, trays, or pouches.
Various attempts to create carts for use with wheelchairs have been made. One of the more practical-appearing examples is U.S. Pat. No. 4,484,755 of Houston. One embodiment of Houston's cart is included in the drawings herein as FIG. 1, labeled “Prior Art.”
Houston's cart 200 is supported by four wheels 210 and is attached to the front of a wheelchair 300 or walker frame (not shown). The axles of all four wheels 210 of cart 200 and the front pair of wheels 310 of wheelchair 300 are offset from the attachment points of wheels 210,310 such that all three pairs of wheels 210,310 are freely pivoting. This arrangement will likely result in unpredictable steering of the cart and wheelchair combination.
Houston does not describe the detailed means by which the user of wheelchair 300 steers cart 200. FIG. 1 shows that the cart and wheelchair combination includes three pairs of pivoting casters 210, 310 in series. The user of wheelchair 300 may need to use “opposite” steering, such as used by the driver of an auto with attached trailer to back up. Actually, the steering is likely to be far more unpredictable than simple opposite steering and the wheelchair/cart combination may tend to lock up during a complicated maneuver, such as a three-point turn in a grocery store aisle.
If Houston's cart 200 were attached to a walker frame with pivoting front wheels, the situation would be the same. Either the cart would swing unpredictably in response to steering of the walker, or the user would need to apply opposite steering and initially move in the direction opposite the turn.
Houston also discloses an embodiment of the cart attached to a walker frame without wheels (not shown). It appears the user of the walker would have to lift the walker and use the elevated walker frame to steer the Houston cart. This would potentially require more muscle power and agility than a typical user of a mobility aid device has, as well as putting the user off-balance with each change of direction.
The Houston cart 200 of FIG. 1 elevates the basket portion well above the castered chassis. The Houston cart 200 clearly has a very high center of gravity; when loaded with articles it could be dangerously top heavy.
Other cargo-carrying carts for use in combination with wheelchairs have been patented. Most of them would not be feasible to use with a walker frame or scooter. None appear to be capable of being steered safely and intuitively by a person using a walker frame.
Thus, there is a need for a safe, convenient cart that can be attached to a mobility aid device, including an electric scooter, a wheelchair, or a walking frame. There is a need for a cart that can be propelled and steered easily by a fragile or even easily-confused person using a mobility device. There is a need for a cart that has a low center of gravity whether empty or heavily loaded and that will not tip. There is a need for a cart that can securely carry a variety of large or oddly-shaped articles. There is a need for a cargo cart that can be easily detached from the mobility device when not needed, that can be stored conveniently, and that can even be used independently of the mobility device.